Investigating Central Contributions to Fatigue Using Non-invasive Brain Stimulation

May 21, 2026 updated by: Vrije Universiteit Brussel

Investigating the Causal Contribution of Neural Oscillations to Neuromuscular Fatigue After Stroke Using tACS

The goal of this interventional study is to understand the contribution of the central components to the manifestation of neuromuscular fatigue in stroke survivors. The study will include adults with a first-ever stroke in the subacute phase.

The main question it aims to answer:

• How does the brain activity contribute to the manifestation of neuromuscular fatigue in stroke survivors?

Researchers will compare stroke participants receiving active vs sham tACS in a single session before the fatiguing contractions to determine whether central changes can influence fatigue onset/progression.

Participants will:

  • Perform repeated leg muscle contractions until fatigue while seated in an experimental setup
  • Receive either active or sham tACS for 20 minutes before the fatiguing contractions.
  • Wear non-invasive sensors to record brain activity (EEG) and muscle activity (EMG) during the task
  • Complete the study during a single experimental session in which fatigue-related changes will be measured throughout the task

Study Overview

Study Type

Interventional

Enrollment (Estimated)

120

Phase

  • Phase 2
  • Phase 1

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

First-ever stroke

≥18 years Subacute phase: 1 week to 6 months post-stroke Quadriceps (hemiplegic side) strength ≤3/5 (Medical Research Council (MRC)) Montreal Cognitive Assessment (MoCA) ≥21

Exclusion Criteria:

History of a previous stroke Severe spasticity (Modified Ashworth Scale (MAS) 3-4 in quadriceps/hamstrings) Other neurological, motor, musculoskeletal, or orthopedic conditions affecting trunk stability and lower limb mobility Non-cerebral strokes (e.g., brainstem, cerebellar), or dementia (MoCA ≤20) Current or former athletes. Athletes are defined as individuals who participated in organized competitive sports and engaged in structured training ≥3 sessions per week for ≥1 year within the 5 years preceding stroke Contraindications for tACS (e.g., presence of a deep brain stimulator, pacemaker, head wound, etc.).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Sham Comparator: Sham tACS
mimics active tACS but stops after 1 minute
Active Comparator: Active tACS
Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique that uses electrodes on the scalp to apply weak alternating electrical currents to the brain.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Absolute and relative spectral power and ERD/ERS magnitude
Time Frame: Outcome measure will be recorded at baseline and throughout the fatiguing contractions in the single experimental session (up to 40 minutes) and compared over 4 fatigue phases.
Fatigue-related changes in sensorimotor cortical activity will be assessed using EEG-derived absolute and relative spectral power in the mu (8-12 Hz), beta (13-30/35 Hz), and gamma (30/35-100 Hz) frequency bands, as well as changes in event-related desynchronization/event-related synchronization (ERD/ERS) magnitude over time. Measurements will be obtained at pre-fatigue baseline and continuously during the fatiguing task, with data segmented into contraction epochs and grouped into four fatigue phases for analysis.
Outcome measure will be recorded at baseline and throughout the fatiguing contractions in the single experimental session (up to 40 minutes) and compared over 4 fatigue phases.
EMG median frequency
Time Frame: Outcome measure will be recorded throughout the fatiguing contractions in the single experimental session (up to 40 minutes) and compared over 4 fatigue phases.
Peripheral manifestations of fatigue will be assessed using shifts in EMG median frequency during repeated contractions. Data will be recorded continuously during the task and analyzed across contraction epochs grouped into four fatigue phases.
Outcome measure will be recorded throughout the fatiguing contractions in the single experimental session (up to 40 minutes) and compared over 4 fatigue phases.
Time-to-task failure (TTF)
Time Frame: Outcome measure will be recorded throughout the fatiguing contractions until exhaustion
The duration a participant can sustain the prescribed fatiguing exercise until exhaustion
Outcome measure will be recorded throughout the fatiguing contractions until exhaustion

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Corticomuscular coherence
Time Frame: Outcome measure will be recorded throughout the fatiguing contractions in the single experimental session (up to 40 minutes) and compared over 4 fatigue phases.
The interaction between cortical and muscular activity will be assessed using CMC, which quantifies synchronization between EEG and EMG signals. Corticomuscular coherence will be assessed from simultaneous EEG and EMG recordings during repeated contractions and analyzed across contraction epochs grouped into four fatigue phases.
Outcome measure will be recorded throughout the fatiguing contractions in the single experimental session (up to 40 minutes) and compared over 4 fatigue phases.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

September 1, 2026

Primary Completion (Estimated)

October 31, 2029

Study Completion (Estimated)

October 31, 2029

Study Registration Dates

First Submitted

May 21, 2026

First Submitted That Met QC Criteria

May 21, 2026

First Posted (Actual)

May 29, 2026

Study Record Updates

Last Update Posted (Actual)

May 29, 2026

Last Update Submitted That Met QC Criteria

May 21, 2026

Last Verified

May 1, 2026

More Information

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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